Silicon dioxide (SiO2) is in common use in the semiconductor industry, typically as an insulator. To create a desired insulating structure, a silicon dioxide film may be applied first. The silicon dioxide film may be applied in different ways, such as by means of atomic layer deposition (ALD). ALD is an advantageous option as it results in the deposition of high quality spatially uniform, conformal and dense films. Once a silicon dioxide film has been deposited, undesired portions of the applied film may be selectively etched away to create the aforementioned structure, commonly through wet etching using a hydrofluoric acid (HF) solution. In other applications, undesired portions of additional films deposited over the silicon dioxide film, instead of the silicon dioxide film itself, may be selectively etched away to create the aforementioned insulating structure in a similar manner. An important parameter in wet etching is the wet etch rate, i.e. the rate of material removal. Although the wet etch rate may be expressed independent-ly in for example nano- or micrometers per minute, it is often phrased in terms of a wet etch rate ratio (WERR). Given certain process conditions—e.g. the choice of etchant, its concentration and the temperature at which the etching takes place—the WERR of a film may be calculated by dividing the wet etch rate of the film by the wet etch rate of thermal silicon dioxide. Thermal silicon dioxide, often briefly referred to as ‘thermal oxide’, may be created through thermal oxidation of a silicon wafer surface. It is a highly stable and pure oxide with a relatively low etch rate, and is frequently used as a reference.
For many applications silicon dioxide-based, ALD-depositable films having either a low or a high WERR—with hydrofluoric acid as the etchant—are desirable. It is an object of the present invention to provide for such a film and for a method for manufacturing the same.